Wireless-telegraph receiving apparatus.



S. M. KINTNBR 61 J. W. LEE.

WIRELESS TELEGRAPH RECEIWNL' APE'ABAT H.

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UNITED. STATES LITENT orrron SAlllUEL M. KINTNER, or PITTSBURGH, PENNSYLVANIA, AND .ioHNw. LEE, or BRANT ROCK, MASSACHUSETTS, ASSIGNORS, BY MESNE ASSIGNMENTS, To SAMUEL M. KINTNER, or PITTSBURGH, PENNSYLVANIA, AND HALSEY m. BARRETT, or BLOOM- F-IEL'D, NEW JERSEY. RECEIVERS.

WIRELESS-TELEGRAPH BEGEIVING APPARATUS.

Specification of Letters Patent.-

Patented Mar. 23-, 1915.

Application filed June 24, 1912.- Serial No. 705,484.

0 all whom it may concern:

Be it known that We, o'er 5on1. NLIKINTNER and JOHN Vt. LEE, citizens of the United States, residing, respectively, at Pittsjourgh, Pennsylvania, and Brant Rock, li lassa chusetts, have invented certain'new and useful Improvements in lVircless-Telegraph Receiving Apparatus, of which the following is a soeciiication.

Our invention relates more particularly to receivers for wireless telegraphy of the type known as Fessendens heterodyne receiver ;that is, a receiving system in wh ch the signal is produced by combining with the energy of the received electromagnetic Waves, certain similarly timed locally produced impulses, which co-act with the re- Qceived impulses; the indication being produced by the conjoint action of the two sources of energy. In such receivers the tuning is-of course very close and interference very little and consequently it is not so easy to find by trial, an incoming wave length not known beforehand.

The primary object of our invention is to combine with the heterodyne receiver, a ready andeasily operated finding receiver.

We have illustrated the apparatus in one form in the accompanying drawing, wherein-Figure 1 is a diagram showing a receiving apparatus embodying our invention and Fig. 1 is a detail view of a convenient ar rangein'ent of mechanically connected tuning coils, preferably used therein. Fig. 2 is a modification of the invention using separate transformers for a receiver and a local generating circuit. Fig. 3 is a detail snatch oi the coupled tuning condensers, preferably used.

In Fig. 1 or" the drawing, we represent a receiving antenna circuit from capacity 4 to ground at 5, which includes a variable condenser 6 shunted by the electrostatic telephone receiver 7; below this another condenser 8, shunted by a switch 9 by which it may he cut out, the primary 10 of a transformer, and a variable tuning inductance 11. The secondary 12 of the transformer is connected as by switch 131:0 a local generating circuit, or alternately by, throwing the switch.

13, to a local receiving circuit, comprising a condenser 14, detector 15, indicating telephone 16 and potentiometer 17. The local generating circuit connected to the secondary 12 comprises a tuning inductance 18, one or more capacities 19, an are 20, a variable impedance' 21, and a local current source 22.

As explained more fully in various patents of l essenden, the heterodyne receiver operates briefly in this wise: The received wave currents flowing in the primary 10, are periodically augmented in their efiects on the receiver 7 by locally produced oscillations generated in the secondary 12, by reason of the oscillations produced in the circuit 18,19, 20, through discharge of the current from 22, through the are 20. Preferably the periodicity of the circuit 12, 18, 19, 20, is very close to but not the same as the periodicity of the antenna and the circuit 6, 7, and this produces beats which have an augmented effect upon the receiver 7. The operation of this heterodyne receiver requires that the relative periodicities of the antenna, and the oscillating circuit excited by the local source, shall be maintained in very exact condition and all the said circuits very closely tuned. t will be understood that this device practically cuts out the effect of all waves except those having a periodicity with exactly the proper relation to the periodicity of the oscillations in coil 12, produced by the local source. Therefore it is not easy to iind a'signal of a different periodicity not known to the operator. We prefer to arrange the tuning coils 11 and 18, respectively, in the antenna and the local circuits in some mechanical connection, such as illustrated at Fig. 1, such that the tuning sliders upon the two coils move simultaneously and with the same or a roportional effect. That is to say in changing the tune of one circuit We change in like manner the tune of the other circuit. By throwing the switch 13 to the contacts 13, the heterodyne generating circuit is cut out and the ordinary detector circuit 14:, 15, 16, 17, is cut .in, and this is preferably arranged with What is called a broad tune, so that it can pick up various waves. The operator listening on the telephone 16 tunes the antenna by shiftin the inductance 11 until he gets in tune Wlth recei'ved Waves, and in doing so hassimultaneously shifted the tune of the circuit 12, 18, 19, 20, so that the operator further adjustments to secure maximum 5; for tuning, We preferably mount these two capacities, with a mechanical connection,

such for example as shown in Fig. 3, by which they are likewise varied in unison. By this arrangement the operator may rapidly run over various ranges of wave length within the limits of the heterodyne set and pickup any desired station and thereupon by the mere movement of the switch 13 receive without interference upon the heterodyne receiver, or, he may make selectivity.

In Fig. 2, Wehave arranged to secure a better coupling for use of the ordinary detector circuit. That is, We use a separate secondary 23 to connect the local receiving circuit 14, 15, 24, 16, 17. Otherwise the operation is as above described.

Having thus described our invention and illustrated its use, what we claim is the following:

1. The combination with a highly selective closely tuned wireless telegraph receiving set, of a supplementary broad tuned receiver, and means for tuning the antenna circuit to cause the broadly tuned receiver to respond with maximum efi'ect and arranged tosimultaneously vary the tune of 4 the closely tuned. receiving set. A

2 The combination with a receiving an tenna, of a receiver connected. thereto and operating by combined efiects of received and locally produced oscillations, a supple- 4. in wireless telegraph apparatus, the combination or an antenna, a local generating source of oscillations, a receiver operated by the combined efiects of the received and locally generated oscillations, a finding receiver operatively connected to the antenna,

and means for simultaneously tuning the 1- antenna and the local oscillation producing circuit.

In testimony whereof, We have hereunto signed our names in the presence of the two subscribed w1tnesses.

SAMUEL M. nm'rua n JOHN W. ea. T

Witnesses for Samuel M. K'intner JEssIn E. B NT, F EDK STAUB.

Witnesses llor John W. Lee 1 LOUIS COHEN,

ELLIOTT W.- CRO. 

